WO2014156721A1

WO2014156721A1 - Ship provided with bubble resistance reduction device, and method for reducing resistance of ship

Info

Publication number: WO2014156721A1
Application number: PCT/JP2014/056877
Authority: WO
Inventors: 浩明横田
Original assignee: 三井造船株式会社
Priority date: 2013-03-25
Filing date: 2014-03-14
Publication date: 2014-10-02
Also published as: KR101616261B1; CN105189278B; JP2014184877A; CN105189278A; JP5599482B1; KR20150058570A

Abstract

A ship (1) provided with a bubble resistance reduction device for supplying air bubbles or a gas-liquid mixed fluid from an air bubble supply hole (10) provided to a hull (2), and leading the air bubbles to the bottom of the ship to reduce the friction resistance of the hull (2), wherein a bow bulb (3) provided to the bow of the ship is configured from a downward-flow-promoting type of bow bulb having an increased effect of leading flowing water in the bow portion to the bottom of the ship. The tip position (Pb) of a ship-bottom flat part (2f) is between X2, which is rearward from a forward perpendicular (F.P.) by at least 0.7% of a length between perpendiculars (Lpp), and X1, which is rearward by no more than 5% of the length between perpendiculars (Lpp). Air bubbles supplied from the air bubble supply hole (10) can thereby be led efficiently to the ship-bottom flat part (2f), and the air bubble supply energy for reducing the hull resistance can be reduced.

Description

Ship equipped with bubble resistance reduction device and ship resistance reduction method

The present invention provides a ship equipped with a bubble-type resistance reducing device that supplies bubbles or gas-liquid mixed fluid from a bubble supply hole provided in a hull and induces the bubbles to the bottom of the ship to reduce the frictional resistance of the hull. More specifically, the present invention relates to a resistance reducing method, and more particularly, to provide a bubble type resistance reducing apparatus capable of efficiently guiding bubbles supplied from a bubble supply hole to a flat part of a ship bottom and reducing bubble supply energy for reducing hull resistance. The present invention relates to a ship provided and a resistance reduction method of the ship.

The reduction of ship resistance has a close relationship with the reduction of energy required for operation of the ship and the reduction of carbon dioxide generation from the internal combustion engine mounted on the ship, and is related to recent environmental problems and rising fuel costs. It has become an increasingly important technical theme due to fuel consumption problems. Among the elements of hull resistance, the frictional resistance of the submerged hull surface accounts for a large percentage, and it is important to reduce the frictional resistance of the hull in relation to the reduction of energy for ship propulsion. A method for reducing frictional resistance by supplying air bubbles such as air bubbles and microbubbles to the surface of a low-friction paint or a hull has been researched and developed, and is being implemented on a commercial ship.

In this connection, for example, as described in Japanese Patent Application Laid-Open No. 2010-208435, water that has absorbed carbon dioxide from the outside of the ship after separating carbon dioxide contained in the exhaust gas of the internal combustion engine of the ship is separated. A mixture of fine bubbles of carbon dioxide generated from water that has been injected from high pressure to low pressure after being injected from the bow side toward the stern side after being mixed and dissolved under high pressure. There has been proposed a ship resistance reduction device that greatly reduces the fluid resistance of the outer surface of the ship bottom by using (microbubbles) and enhances the energy effect of the boat propulsion device (see Patent Document 1).

However, in the method of reducing the frictional resistance by supplying these bubbles to the surface of the hull, in order to supply a sufficient amount of bubbles to the flat part of the bottom of the ship having a large area, the bubbles are supplied from the ship bottom to the water. However, when supplying bubbles directly to the bottom of the ship, the water depth at the bottom of the ship is deep and the static pressure is high, so there is a problem of supply pressure that increases the energy for supplying the bubbles. When this problem occurs, even if the resistance reduction effect by the bubbles is obtained, the energy consumption for supplying the bubbles increases, and the energy saving effect as a whole decreases.

This problem of supply pressure is less severe on ships with relatively shallow drafts. However, on merchant ships with deep drafts such as ordinary tanker ships and bulk carriers (bulk carriers), the bubble supply holes are located on the side of the ship other than the bottom. However, as the position of the bubble supply hole becomes deeper than the surface of the water, the pressure required to overcome the water pressure at this site and push out the bubble or gas-liquid mixed fluid increases. The amount of energy required to supply the energy increases. If the amount of energy required to supply the bubble or gas-liquid mixed fluid is large, the energy saving effect due to the resistance reduction effect is reduced. Therefore, in this bubble type resistance reduction method, the bubble or gas-liquid mixed fluid is supplied. It is important to minimize the amount of energy required to do this.

In relation to this supply pressure problem, for example, as described in Japanese Patent Application Laid-Open No. 2012-224111, a plurality of positions (specifically, the bottom of the ship) A plurality of gas blowing portions provided on both sides of the ship and capable of blowing out gas, and a plurality of gas supplies provided corresponding to the plurality of gas blowing portions and supplying gas to the plurality of gas blowing portions There is proposed a frictional resistance-reducing ship that is equipped with a device and that can be efficiently implemented with reduced energy consumption (see Patent Document 2).

However, the ratio of the bubbles or gas-liquid mixed fluid ejected from the bubble supply holes to the ship bottom flat part having a large area away from the hull surface decreases, and therefore the amount of bubbles or gas-liquid mixed fluid ejected increases. If so, there is a problem of hull separation that the energy for ejection increases. If this problem arises, even if the resistance reduction effect by a bubble is acquired, the consumption of bubble supply energy will increase and the energy saving effect as a whole will decrease.

In relation to the separation of the bubbles from the hull surface, for example, as described in Japanese Patent Laid-Open No. 10-16876, compressed air is supplied from a pressurized air supply device through an air supply pipe to a number of air outlets. The air blower, which is designed to blow out from the water and generate microbubbles, is in the submerged portion of the ship side skin at the bow and into the region where the streamlines determined according to the hull shape flow along the hull surface. In addition, there has been proposed a ship frictional resistance reduction device having a configuration in which the height of the bow side and the stern side are assembled in different postures so that most of the generated microbubbles flow on a streamline (see Patent Document 3). ).

Further, for example, as described in Japanese Patent Application Laid-Open No. 9-183396, at a position on the streamline that is directed to the bottom of the ship at the inundation portion of the bow of the hull, and at a position with a small static pressure, Air vents are provided, and the microbubbles generated by the blowout of pressurized air at the air outlets are circulated along the streamline to the bottom of the ship to generate the required void ratio, and at the time of navigation A hull frictional resistance reduction method for reducing the hull frictional resistance has been proposed (see Patent Document 4).

However, in this ship frictional resistance reduction device, the position of the air outlet is aligned with the streamline of the existing hull shape, but the downward flow toward the bottom flat part of the hull shape and bow valve shape from the upper bow is positively positive. The technical idea of reducing the supply energy of the microbubbles and increasing the frictional resistance reduction effect by the microbubbles is not conceived.

Further, in the conventional friction resistance reducing ship, since the gas blowing part is provided only in the part below the draft line on the still water surface of the ship on the ship side, the water level rises at the bow part when the ship is sailing. As the depth of submergence increases, a greater static pressure is applied than when the ship is stopped in still water, but this is not taken into account.

Japanese Unexamined Patent Publication No. 2010-208435 Japanese Unexamined Patent Publication No. 2012-224111 Japanese Unexamined Patent Publication No. 10-16876 Japanese Unexamined Patent Publication No. 9-183396

The inventor of the present invention rectifies the flow of the bow part by reducing the resistance effect by the interference between the wave generated by the bow valve and the wave generated by the hull, so-called wave resistance reduction effect, Bubbles supplied from a bubble-type resistance reduction device, focusing on the effect of lowering the water flow of a specially shaped bow valve, while designed to reduce the wave breaking resistance and wave resistance of the bow I came up with the technical idea that the bow valve can be used to efficiently supply the to the flat part of the bottom of the ship.

Further, the present inventor has not conventionally considered the relationship between the shape of the bottom of the bow and the flow of the water flow to the flat portion of the bottom of the boat. Note that the water flow at the bow flows into the flat part of the bottom of the ship when it is configured more gently than the hull shape of the hull. I came up with the technical idea that it could be used to supply.

Furthermore, the inventor of the present invention relates to the fact that the energy of supply of bubbles or gas-liquid mixed fluid from the bubble supply hole of a ship equipped with a conventional bubble resistance reduction device is related to the water pressure of the bubble supply hole, and during navigation, As shown in FIG. 15, in consideration of the fact that the water level rises in the bow part, the bubble supply hole pressure is increased as much as possible to reduce the pressure of the bubble supply hole as much as possible. We came up with the technical idea that by reducing the amount of energy at the time of supply as much as possible, the amount of bubble supply energy for reducing resistance in ships that operate for a long time can be reduced.

The present invention has been made in view of the above situation, and an object of the present invention is to supply air bubbles or a gas-liquid mixed fluid from air bubble supply holes provided in the hull and induce the air bubbles to the bottom of the hull to friction of the hull. In a ship equipped with a bubble-type resistance reduction device that reduces resistance, the bubbles supplied from the bubble supply holes can be efficiently guided to the flat part of the bottom of the ship, reducing the amount of bubble supply energy to reduce the hull resistance. Another object of the present invention is to provide a ship having a bubble-type resistance reducing device and a ship resistance reducing method.

In order to achieve the above object, a ship equipped with the bubble resistance reducing device of the present invention supplies bubbles or a gas-liquid mixed fluid from a bubble supply hole provided in the hull to guide the bubbles to the bottom of the ship. In a ship equipped with a bubble resistance reducing device that reduces the frictional resistance of the hull, the navigation speed of the ship is Vs (m / s), the gravitational acceleration is g (m / s ² ), and (0.5 × Vs × Vs) / g, where H (m) is the head of the hull, it is behind the bow vertical position and 0.25 times the length between the vertical from the bow perpendicular to the front and rear direction of the hull. The bubble supply hole group is arranged in front of the position, and the bubble supply hole of the bubble supply hole group is higher in the vertical direction of the hull than the portion that is twice as low as the water head H from the full load water line. A bow valve at the bow, and the bow valve It is comprised so that a bu may be formed with the bow valve | bulb of the downflow promotion type | mold which guides the flow of the water flow in a bow part to a ship bottom part.

According to this configuration, since the bow valve is configured by the downward flow promotion type bow valve, the bubbles supplied from the bubble supply hole can be more efficiently sent to the bottom of the ship by the downward flow at the bow portion. .

In a ship provided with the above-described bubble resistance reducing device, the tip position of the flat bottom portion is provided in a range of 0.7% or more of the vertical line length and 5% or less of the vertical line length behind the bow vertical line. Is done.

According to this configuration, by arranging the tip of the flat bottom portion behind the bow perpendicular by 0.7% or more of the length between the perpendiculars, the lower part of the hull of the bow becomes a gentle slope and the ship bottom It becomes a shape which continues to a flat part, and it becomes easy to guide the water flow of a bow part in a ship bottom flat part. Therefore, the flow around the hull of the bow including the bubbles supplied from the bubble supply holes is guided by this flow and flows into the ship bottom flat part, and the bubbles can be efficiently fed into the ship bottom flat part. In addition, if it is 5% or more rearward of the upper limit perpendicular length (Lpp), the lower slope of the hull becomes too gentle, and the effect of inducing this bubble to the bottom part of the ship bottom becomes small. The advantage of retreating the position of the bow end to the back will be lost.

In the ship equipped with the bubble resistance reducing device, in the cross-sectional shape at the center between the bow normal and the tip position of the bow valve in the longitudinal direction of the hull, 55% or more of the cross-sectional area of the bow valve is more than 55%. The cross-sectional shape is formed so as to be above the center height in the vertical direction, and the valve volume above the center height between the bow normal and the tip position of the bow valve in the longitudinal direction of the hull. Is configured to be 1.1 times or more and 4.0 times or less of the valve volume below the central height.

According to this configuration, a relatively simple bow valve shape can be used to form a downflow promotion type bow valve, and the bubble or gas-liquid mixed fluid supplied near the full load water line is led from the ship side to the bottom of the ship by the downflow. Thus, the bubbles can be efficiently sent to the bottom of the ship.

Further, it is more preferable that the bow valve has a shape in which the lower end of the bow valve rises forward in a side view.

In a ship equipped with the above-described bubble resistance reducing device, when the draft on the bow perpendicular line in a full load state is df, the uppermost point of the bow valve at the center position is 0. 0 than the full load draft line and the full load draft line. It is provided so as to be positioned between 2 × df and the maximum width of the bow valve is 0.2 × df lower than the full load water line and 0.6 × df lower than the full load water line. It is provided and configured so as to be located between these parts.

According to this configuration, the submerged depth of the upper surface of the bow valve becomes a depth suitable for promoting the downward flow, and the shape of the bow valve can be further enhanced to promote the downward flow.

In a ship equipped with the above-described bubble resistance reduction device, if a guide groove or a guide member for guiding the downward flow at the bow is provided on the hull surface of the bow, the bubbles can be supplied to the bottom of the ship more efficiently. it can.

In the ship provided with the above-described bubble resistance reduction device, the bubble supply hole of the bubble supply hole group is moved from the part lower than the full load water line by a factor of twice the full head water line with respect to the vertical direction of the hull. It is arranged and configured to include a range up to a portion higher than the head H. In addition, the ship here includes not only a ship capable of navigating but also a towed ship such as a barge. In addition, the bubble supply holes provided in the hull include not only the bubble supply holes penetrating the hull surface but also the bubble supply holes of the pipes provided along the hull surface.

According to this configuration, since the bubble supply hole is provided up to the portion above the full-length water line that has not been arranged in the prior art, the bubble supply hole when supplying the bubble or gas-liquid mixed fluid into water during navigation is provided. The submerged position becomes shallower, and the supply pressure of the bubbles or gas-liquid mixed fluid supplied to the bubble supply hole can be reduced accordingly, and the amount of energy for supplying bubbles can be saved, and ship propulsion The total amount of energy for use can be reduced.

The head H is a head when the water flow at the flow velocity Vs is held down when navigating at the voyage speed Vs, and the position above the full load water line is H. The height is considered to be the maximum water level around the hull at the time, and the height of the head H takes this into consideration. Although the bubble supply hole may be arranged at a higher position in consideration of the incident wave, it takes a long time to be exposed to the air and becomes impractical.

In the ship provided with the above-described bubble resistance reduction device, the bubble supply hole of the bubble supply hole group in the vertical direction of the hull is lower than the ballast water line by 2 times the head H, than the ballast water line. It is configured so as to include a range up to a portion higher than the head H. According to this configuration, the amount of energy for supplying bubbles can be saved when navigating in a ballast state as well as when navigating in a full load state, and the total amount of energy for ship propulsion can be reduced. Can be reduced.

In a ship equipped with the above-described bubble-type resistance reducing device, a bubble supply stop device for stopping supply of bubbles or gas-liquid mixed fluid is provided for one or a plurality of the bubble supply holes of the bubble supply hole group, In the state where the bubble supply hole is not submerged, the supply of bubbles or gas-liquid mixed fluid to the bubble supply hole which is not submerged is stopped.

According to this configuration, when navigating at a reduced navigation speed or when navigating with a draft other than the full load water line, the bubble supply hole near the full load water line may not be submerged. Since the pressure of the supply hole is remarkably lowered and the bubbles or gas-liquid mixed fluid flows out into the atmosphere, this is prevented and the outflow of useless bubbles or gas-liquid mixed fluid is prevented.

The ship resistance reduction method of the present invention for achieving the above object is a method of using a ship provided with the bubble resistance reduction device. According to these methods, the same effect as a ship provided with the above-described bubble resistance reduction device can be obtained.

According to the ship having a bubble-type resistance reduction device and the ship's resistance reduction method according to the present invention, the bubble or gas-liquid mixed fluid is supplied from the bubble supply hole provided in the hull, and the bubble is guided to the bottom of the ship. In a ship equipped with a bubble resistance reducing device that reduces the frictional resistance of the hull, the bubbles supplied from the bubble supply hole can be efficiently guided to the bottom of the ship, and the bubble supply energy for reducing the hull resistance can be reduced. Can be reduced.

FIG. 1 is a side view showing a bow valve for promoting a downward flow according to an embodiment of the invention. FIG. 2 is a view showing a cross section at the center position of the bow valve of FIG. FIG. 3 is a bottom view showing the relationship between the tip position of the flat portion of the ship bottom and the bow perpendicular. FIG. 4 is a ship bottom perspective view schematically showing the flow of bubbles or gas-liquid mixed fluid to the ship bottom flat part. FIG. 5 is a side view for explaining the first shape of the bow valve that promotes the downward flow. FIG. 6 is a side view for explaining a second shape of the bow valve that promotes the downward flow. FIG. 7 is a side view schematically showing a water flow when a bow valve for promoting a downward flow is attached. FIG. 8 is a side view schematically showing the bubble resistance reduction device. FIG. 9 is a side view showing positions of bubble supply holes for supplying bubbles or gas-liquid mixed fluid when sailing in a full load state. FIG. 10 is a side view showing positions of bubble supply holes for supplying bubbles or gas-liquid mixed fluid when sailing in a ballast state. FIG. 11 is a side view showing the ejection direction of bubbles or gas-liquid mixed fluid in the bubble supply holes. FIG. 12 is a side view showing a guide groove that guides bubbles or gas-liquid mixed fluid to the ship bottom. FIG. 13 is a side view showing a guide member that guides bubbles or gas-liquid mixed fluid to the ship bottom. FIG. 14 is a diagram illustrating a configuration of the bubble supply system. FIG. 15 is a partial side view of the bow for explaining the rise of the water level in the bow. FIG. 16 is a side view schematically showing a water flow when a conventional bow valve is mounted.

Hereinafter, a ship equipped with a bubble-type resistance reduction device and a ship resistance reduction method according to an embodiment of the present invention will be described with reference to the drawings. A ship (hereinafter referred to as a ship) equipped with a bubble resistance reduction device according to an embodiment of the present invention supplies bubbles or gas-liquid mixed fluid from a bubble supply hole provided in the hull, and the bubbles are supplied to the bottom of the ship. It is a ship provided with a bubble type resistance reducing device that induces and reduces the frictional resistance of the hull. It should be noted that the bubble supply holes provided in the hull include not only the bubble supply holes penetrating the hull surface but also the bubble supply holes of piping provided along the hull surface.

As shown in FIG. 1, FIG. 2, FIG. 3, and FIG. 4, the bow valve 3 provided at the bow portion of the ship 1 promotes the generation of a downward flow that introduces the water flow at the bow portion into the flat bottom portion 2f. It is composed of a downflow promotion type bow valve that is shaped to allow

Further, as shown in FIG. 8, a ship-side outer plate 2 a is disposed on the side surface of the hull 2 of the ship 1, and a ship bottom flat portion 2 f serving as a ship bottom is disposed at the lower portion. And a propeller 4 and a rudder 5 are provided at the stern part. An upper structure 6 is provided on the stern.

First, the ship bottom shape will be explained. As shown in FIGS. 3 and 4, in this ship bottom shape, the tip position Pb of the ship bottom flat portion 2 f is set to the bow perpendicular line F.D. P. From the position X1 that is 5% or less of the inter-perpendicular length Lpp to the bow perpendicular line F.P. P. More than 0.7% of the inter-perpendicular length Lpp to the rear position X2, more preferably the bow perpendicular F.V. P. From the position of 4% or less of the inter-perpendicular length Lpp, the bow perpendicular F. P. More than 2% of the inter-perpendicular length Lpp, the range to the rear position. That is, the bow end position 2fp (= tip position Pb) of the flat bottom line 2fa indicating the outer periphery of the ship bottom flat portion 2f is the bow perpendicular line F.P. P. More than 0.7% of length Lpp between perpendiculars, it is constituted so that it may be on the stern side.

With this configuration, in a side view, the lower portion 2d of the bow 2 of the bow portion is gently inclined to be continuous with the flat bottom portion 2f, and the water flow W at the bow portion is guided into the flat bottom portion 2f. It becomes easy to be done. Therefore, the flow around the hull at the bow is guided by this flow W and flows into the flat bottom portion 2f so that the bubbles supplied from the bubble supply holes 10 can be efficiently fed into the flat bottom portion 2f. Become.

In addition, at the position X1 of 5% or less of the upper limit perpendicular length Lpp, the lower slope of the hull 2 becomes too gentle in a side view, and the guidance of the bubbles to the ship bottom flat portion 2f becomes small. The position where the merit of retreating the bow end position 2fp of the bottom line 2fa disappears.

1 and FIG. 2, the bow valve 3 of the forward flow promoting type of the ship 1 is a bow perpendicular line F.V. P. And 55% or more of the cross-sectional area of the bow valve 3 is above the center height Hm in the vertical direction of the cross-sectional shape in the cross-sectional shape at the center position Pm between the front end position Pf of the bow valve 3 To form. At the same time, the bow perpendicular F. P. And the tip position Pf of the bow valve 3 so that the valve volume above the center height Hm is 1.1 times or more and 4.0 times or less than the valve volume below the center height Hm. To form.

In addition, the bow perpendicular line F. P. When the bow draft at ft is df, the bow perpendicular F.F. P. At the center position Pm of the tip position Pf of the bow valve 3, the uppermost point 3u of the bow valve 3 is the full load water line D.E. W. L. Full load water line W. L. And the maximum width Bb of the bow valve 3 is set to the full load water line D.D. W. L. The part Ha and the full load water line D.0.2 × df min. W. L. It is provided so as to be located between the portions Hb lower by 0.6 × df.

According to the configuration of the bow valve 3 of this downward flow promotion type, the submerged depth of the uppermost point 3u of the bow valve 3 becomes a depth suitable for promoting the downward flow, and the shape of the bow valve 3 is further increased. It can be made into a shape that promotes downward flow. By configuring the bow valve 3 with the downward flow promotion type bow valve 3, the bubbles supplied from the bubble supply hole 10 can be more efficiently sent to the ship bottom flat portion 2f by the downward flow at the bow portion. .

Further, as shown in FIG. 5, the upper end 3 a of the bow valve 3 is made horizontal, or as shown in FIG. 6, the upper end 3 a of the bow valve 3 is placed at the center position from the rear of the center position Pm of the bow valve 3. The front side is made higher than Pm. With these shapes, compared to the bow valve 3X of the prior art ship 1X shown in FIG. 16, as shown in FIG. 7, the generation of the downward flow that introduces the water flow W at the bow portion into the ship bottom flat part 2f is generated. It becomes the shape which promotes more.

As shown in FIG. 8, the bubble supply hole group 10 </ b> A is behind the bow normal (FP) position and has a bow perpendicular F.P. P. From the position Xf behind 0.25 times the vertical length Lpp. Regarding the height direction of the bubble supply hole 10, considering the case of sailing in a full load state, as shown in FIG. 9, the bubble supply hole 10 on the ship side 2 a of the bubble supply hole group 10 </ b> A is connected to the full load water line D.D. W. L. The full load water line from the portion H1 that is twice as low as the head H. W. L. It is arranged including the range R1 up to the portion H2 higher than the head H.

8, 9, and 10, the dotted line indicates the height position of the bubble supply hole 10, and the full load draft line D.D. W. L. And does not indicate the actual injection direction. Nor does it indicate the direction of flow.

The head H (m) is H = (0.5 × Vs × Vs) / where Vs (m / s) is the navigation speed of the ship and g (m / s ² ) is the gravitational acceleration. It is a value calculated by g. As shown in FIG. 15, this head H is a head when the water flow at the flow velocity Vs is held down when navigating at the voyage speed Vs. W. L. The position H0 above the head H is a height that is considered to be the maximum water level around the hull when navigating in plain water at the voyage speed Vs.

構成 According to this configuration, the full flooded water line D. which was not arranged in the prior art. W. L. Since the bubble supply hole 10 is provided up to the upper part H2, the submergence depth of the bubble supply hole 10 at the time of navigation becomes shallow, and accordingly, the bubbles or gas-liquid mixed fluid supplied to the bubble supply hole 10 is reduced. The supply pressure can be reduced, the amount of energy for supplying bubbles can be saved, and the total amount of energy for vessel propulsion can be reduced. In consideration of the incident wave, the bubble supply hole 10 may be disposed at a higher position, but the exposure time to the air becomes long, which is not practical.

When sailing in a full load state, by supplying bubbles or gas-liquid mixed fluid from these bubble supply holes 10, the amount of energy for supplying bubbles is saved with a small supply pressure, and the bubbles are supplied to the ship bottom flat portion 2f. The friction resistance can be reduced.

Further, as shown in FIG. 10, in consideration of the case where the ship 1 navigates in a ballast state in which the full load state and the draft are greatly different, the bubble supply hole 10 of the bubble supply hole group 10 </ b> A is ballasted in the vertical direction of the hull. Waterline L. W. From the part H3 that is twice as low as the head H, the ballast water line L. W. L. It is configured so as to include the range R2 up to the portion H4 higher than the head H. According to this configuration, the amount of energy for supplying bubbles can be saved when navigating in a ballast state as well as when navigating in a full load state, and the total amount of energy for ship propulsion can be reduced. Can be reduced.

When sailing in a ballast state, by supplying bubbles or gas-liquid mixed fluid from these bubble supply holes 10, the amount of energy for supplying bubbles can be saved with a small supply pressure, and the bubbles are supplied to the ship bottom flat portion 2f. The friction resistance can be reduced.

The arrangement of the bubble supply holes 10 with respect to the ballast state is particularly effective in the case of a ship whose draft changes greatly in a full state and a ballast state such as a tanker ship, a bulk cargo ship that carries heavy objects such as ore and coal. . Further, the range R1 for the full load state and the range R2 for the ballast state may overlap each other or may be separated depending on the shape of the hull.

Further, as shown in FIG. 11, the jet direction of the bubbles or gas-liquid mixed fluid in the bubble supply holes 10 of the bubble supply hole group 10A is 0 degree (α1) to 50 degrees (α2) from the horizontal in the stern direction downward. ), More preferably within a fan-shaped range (within hatching) within a range of 10 to 40 degrees. When the direction outside this range, for example, the injection direction is directed toward the bow direction, when viewed from the hull side at the time of navigation, the jet flow of bubbles or gas-liquid mixed fluid is caused by the water flow flowing toward the hull 2 It is necessary to extrude the bubble or gas-liquid mixed fluid with a larger pressure so that is not pushed in.

Further, preferably, in order to more efficiently supply air bubbles to the ship bottom flat part 2f, the position of the air bubble supply hole 10 provided in the hull surface and the injection direction are as shown in FIG. Along the guide groove 12 to be guided or as shown in FIG. 13, the position and the injection direction are along the lower side of the guide member 13 such as a guide fin for guiding the water flow downward. Further, it is preferable that the jet direction of the bubbles or the gas-liquid mixed fluid is a direction along a streamline that does not separate from the hull surface, and a direction along a downflow streamline that flows into the bottom flat portion 2f. More preferably.

The bubble supply hole 10 is exposed to the atmosphere because the bubble supply hole 10 is not always submerged under the influence of the loaded state, the navigation speed, the incident wave, and the like. A bubble supply stop device 28 that stops the supply of bubbles or gas-liquid mixed fluid to the branch pipe 26 connected to one or a plurality of bubble supply holes 10 located above the bubble supply hole group 10A. Is provided. When it is determined by the bubble supply stop device 28 that the bubble supply hole 10 is not submerged, that is, is exposed to the atmosphere, the bubble supply hole 10 is not submerged. The supply of bubbles or gas-liquid mixed fluid is stopped.

This allows the ship 1 to navigate in the waves, to navigate at a reduced navigation speed, W. L. The full load water line is used when navigating with a draft other than W. L. When the nearby bubble supply hole 10 is not submerged, the pressure of the bubble supply hole 10 is remarkably lowered to prevent the bubble or gas-liquid mixed fluid from flowing out wastefully.

Next, a bubble supply system 20 for supplying bubbles or gas-liquid mixed fluid to each bubble supply hole 10 will be described with reference to FIG. Regarding the bubble component, it is the outside air (atmosphere), a part of the supercharged air (scavenging) of the internal combustion engine, a part of the exhaust gas of the internal combustion engine, or carbon dioxide separated from the exhaust gas. However, there is no particular limitation in the present invention. As for the bubble supply method, gas may be supplied to the bubble supply hole 10 as it is, or a gas-liquid mixed fluid in which gas is mixed may be supplied to the bubble supply hole 10.

For the bubble supply device that supplies the bubbles directly to the outside of the hull surface, a well-known bubble supply device can be used. For example, as shown in FIG. 8 and FIG. 14, air from a blower 22 driven by an electric motor 21 is directly supplied to each bubble supply hole 10, and a pipe 23 connecting the blower 22 and each bubble supply hole 10. Pressure and flow rate by a pressure regulator 24, a flow rate regulating valve 25, a pressure regulating mechanism 27 such as an orifice provided in a branch pipe 26 to each bubble supply hole 10, and a bubble supply stop device 28 formed by an on-off valve. The air is supplied to each bubble supply hole 10 while adjusting.

Further, a submergence sensor 29A for determining whether or not the bubble supply hole 10 is submerged is provided around each bubble supply hole 10 or in the vicinity of the opening. The submergence sensor 29A causes the bubble supply hole 10 to be When a state where the water is not submerged is detected, the on-off valve 28 provided in the branch pipe 26 of the air bubble supply hole 10 which is not submerged is closed to stop the supply of the air bubble or the gas-liquid mixed fluid. .

Further, a water pressure sensor 29B for detecting the water pressure at the position of the bubble supply hole 10 is provided around each bubble supply hole 10 or in the vicinity of the opening portion, and the water pressure sensor 29B. Accordingly, when the water pressure at the position of the bubble supply hole 10 becomes equal to or higher than a preset pressure value, the on-off valve 28 provided in the branch pipe 26 of the bubble supply hole 10 is closed to thereby mix the bubbles or gas-liquid mixture. The fluid supply is stopped.

These controls are performed by the individual bubble supply control device 20c which inputs detection signals of the submergence sensor 29A and the water pressure sensor 29B and outputs a control signal for controlling the opening / closing of the on-off valve 28. In the individual bubble supply control device 20c, each bubble supply device 11A is arranged to control the supply of bubbles or gas-liquid mixed fluid in the bubble supply holes 10 of each bubble supply hole group 10A arranged on the ship side 2a. At the same time, each of these bubble supply devices 11 </ b> A is connected to a comprehensive bubble supply device 31 that is comprehensively controlled, and is configured to follow the control of this comprehensive bubble supply device 31. It should be noted that the supply of bubbles or gas-liquid mixed fluid may be stopped at the discretion of the vessel operator without using the submergence sensor 29A and the water pressure sensor 29B.

Alternatively, although not particularly illustrated, the air is sucked and compressed by a compressor driven by an electric motor to form high-pressure air, and the high-pressure air is temporarily stored in a storage tank to store the high-pressure air from the storage tank. It may be configured to supply high-pressure air to each bubble supply hole while adjusting the pressure and flow rate with a pressure regulator and a flow rate adjustment valve or on / off valve provided in a pipe connecting the tank and each bubble supply hole. good.

Alternatively, in the internal combustion engine of the main engine, a compressor is driven by the turbine of the supercharging system, and the excess air (combustion air: scavenging) that is supercharged and sent to the main engine is taken out, and this excess air is converted into this While adjusting the pressure and flow rate with a pressure regulator, a flow rate adjustment valve and an on-off valve provided in the pipe connecting the compressor and each bubble supply hole, this excess air is supplied to each bubble supply hole. May be.

When supplying these gases, the shape of a large number of bubble supply holes 10 provided on the surface of the ship-side outer plate, or a microbubble-forming member such as an orifice provided in the bubble supply holes 10 or the bubble supply holes A device is used in which the air to be injected is made into microbubbles by an injection nozzle or the like provided in the vicinity of the inside of the vessel 10 and then flows out to the outside of the hull.

In addition, the gas-liquid mixed fluid supply device for supplying bubbles to the outside of the hull surface by mixing bubbles in the liquid in advance and supplying this gas-liquid mixed fluid to the outside of the hull surface is also known in the art. A fluid supply device can be used.

For example, although not shown, carbon dioxide is separated from the exhaust gas of the internal combustion engine mounted on this ship, and this carbon dioxide is mixed and dissolved under high pressure in water absorbed from the outside of the ship, so that the gas-liquid mixed fluid is By making and injecting this gas-liquid mixed fluid from the bubble supply hole to the surface of the hull, fine bubbles of carbon dioxide (micro bubbles) generated from the high pressure to low pressure water after injection are formed on the hull surface. A feeding device can be used. In this case, the shape of the bubble supply hole does not need to be a shape that generates microbubbles, and the fluid resistance at the time of ejection is reduced.

Further, the ship resistance reduction method according to the present invention is a method using a ship provided with the bubble resistance reduction device.

According to the ship having the bubble-type resistance reduction device having the above-described configuration and the ship's resistance reduction method, the bubble or gas-liquid mixed fluid is supplied from the bubble supply hole 10 provided in the hull 2 and the bubble is guided to the bottom of the ship. Then, in a ship equipped with a bubble resistance reducing device that reduces the frictional resistance of the hull, the bubbles supplied from the bubble supply hole 10 can be efficiently guided to the bottom of the ship, and the bubbles are supplied to reduce the hull resistance. The amount of energy can be reduced.

According to the ship having a bubble-type resistance reduction device and the ship's resistance reduction method of the present invention, the bubble or gas-liquid mixed fluid is supplied from the bubble supply hole provided in the hull, and the bubble is guided to the bottom of the ship. In a ship equipped with a bubble resistance reduction device that reduces the frictional resistance of the hull, the amount of bubble supply energy for reducing the hull resistance can be efficiently guided to the bottom of the ship through the bubble supply hole Can be used for many ships.

1 Vessel (Vessel equipped with bubble resistance reduction device)
2 Hull 2a Ship side skin 2d Lower part 2f of the bow of the bow 2f Flat bottom 2fa Flat bottom line 2fp Flat bottom line tip position 3 Bow valve 3a Bow valve upper end 3u Center position of the bow valve 10A bubble supply hole group 11A bubble supply device 12 guide groove 13 guide member 20 bubble supply system 20c individual bubble supply control device 28 bubble supply stop device A. P. Stern perpendicular Bb Maximum width of bow valve df Draft draft at bow perpendicular W. L. Full load water line P. Bow vertical line g Gravitational acceleration H Water head Ha Part Hb 0.2xdf below the full load water line Hb Part 0.6xdf below the full load water line Hm Vertical direction of the cross-sectional shape at the center position in the longitudinal direction of the bow valve The height H1 of the center is 2 times lower than the full headline H2 H2 higher than the full waterline H3 H3 higher than the ballast waterline H4 H4 higher than the ballast waterline H4 Site L. W. L. Ballast draft line Lpp Vertical line length Pb Tip bottom position Pf Bow valve tip position Pm Bow valve center position Vs Ship navigation speed X1 Position X2 5% behind the length Lpp between the bow perpendiculars From the bow perpendicular Position Xf 0.7% behind the vertical line length Lpp Position 0.25 times the vertical line length Lpp behind the bow vertical line

Claims

In a ship equipped with a bubble-type resistance reducing device that supplies bubbles or gas-liquid mixed fluid from a bubble supply hole provided in the hull and guides the bubbles to the bottom of the ship to reduce the frictional resistance of the hull.
When the navigation speed of the ship is Vs (m / s), the gravitational acceleration is g (m / s 2 ), and the head calculated by (0.5 × Vs × Vs) / g is H (m) ,
With respect to the front and rear direction of the hull, the bubble supply hole group is arranged behind the position of the bow perpendicular and ahead of the position behind the bow perpendicular by 0.25 times the length between the perpendiculars,
With respect to the vertical direction of the hull, the bubble supply holes of the bubble supply hole group are disposed so as to include a range higher than a portion that is twice as low as the head H of the full load water line,
Further, a ship provided with a bubble resistance reduction device, characterized in that a bow valve is provided at the bow, and the bow valve is formed by a downflow promotion type bow valve that guides the flow of water flow at the bow to the bottom of the ship. .
2. The bubble resistance reduction according to claim 1, wherein a tip position of the flat portion of the ship bottom is provided in a range of 0.7% or more rearward of the perpendicular length and 5% or less rearward of the perpendicular length from the bow perpendicular line. Ship equipped with equipment.
In the cross-sectional shape at the center between the bow normal and the tip position of the bow valve in the longitudinal direction of the hull, 55% or more of the cross-sectional area of the bow valve is higher than the center height in the vertical direction of the cross-sectional shape. While forming to be on the upper side,
The valve volume above the center height is 1.1 times or more and 4.0 times the valve volume below the center height between the bow normal and the tip position of the bow valve in the longitudinal direction of the hull. The ship provided with the bubble-type resistance reduction device according to claim 1 or 2, wherein the ship is formed as follows.
When the draft on the bow perpendicular line in the full load state is df, the uppermost point of the bow valve is located between the full load water line and a portion 0.2 × df below the full load draft line at the center position. And provided in
The maximum width of the bow valve is provided so as to be positioned between a part 0.2 × df below the full load water line and a part 0.6 × df below the full load water line. A ship equipped with the bubble resistance reducing device according to any one of claims 1 to 3.
5. A ship equipped with a bubble resistance reduction device according to claim 1, wherein a guide groove or a guide member for guiding a downward flow at the bow is provided on a hull surface of the bow.
With respect to the vertical direction of the hull, the bubble supply holes of the bubble supply hole group are arranged to include a range from a portion that is twice as low as the head H to the full load water line to a portion that is higher than the full load water line by the water head H. A ship equipped with the bubble resistance reducing device according to any one of claims 1 to 5.
With respect to the vertical direction of the hull, the bubble supply holes of the bubble supply hole group are arranged to include a range from a portion that is twice as low as the head H to a ballast water line to a portion that is higher than the ballast water line by the height H. A ship provided with the bubble resistance reducing device according to any one of claims 1 to 6, wherein the ship is provided.
In the state where the bubble supply hole is not submerged by providing a bubble supply stop device for stopping supply of bubbles or gas-liquid mixed fluid to one or a plurality of the bubble supply holes of the bubble supply hole group. The ship equipped with the bubble-type resistance reducing device according to any one of claims 1 to 7, wherein supply of bubbles or gas-liquid mixed fluid to the bubble supply holes that are not submerged is stopped.
A ship resistance reduction method using a ship provided with the bubble resistance reduction device according to any one of claims 1 to 8.